Lex orandi, lex credendi

Lex orandi, lex credendi (Latin: "the law of what is prayed [is] the law of what is believed"), sometimes expanded as Lex orandi, lex credendi, lex vivendi (Latin: "the law of what is prayed [is] what is believed [is] the law of what is lived"), is a motto in Christian tradition, which means that prayer and belief are integral to each other and that liturgy is not distinct from theology. It refers to the relationship between worship and belief. Its simplistic applicability as a self-standing principle independent of hope and charity was bluntly denied by Pope Pius XII, who positioned liturgy as providing theological evidence not authority.

Origin
The original maxim is found in Prosper of Aquitaine's eighth book on the authority of the past bishops of the Apostolic See concerning the grace of God and free will: "ut legem credendi lex statuat supplicandi."

"Let us consider the sacraments of priestly prayers, which having been handed down by the apostles are celebrated uniformly throughout the whole world and in every Catholic Church so that the law of praying might establish the law of believing' (emph. added)"

Credendi" and "supplicandi" are gerunds which are oblique cases of the infinitive, and so can be translated into English as "of praying/believing," or just "of prayer/belief," respectively.

Theologian Paul V. Marshall warns "many writers strip Prosper's original ut legem credendi lex statuat supplicandi of "ut" and ignore the function of statuat as the subjunctive of statuere, and so read the dictum as though it were an axiom.[...] (Prosper's) dictum evolved into the simplistic equation, lex orandi lex credendi, and liturgical material is employed in a hierarchical and sometimes authoritarian manner."

In the interpretation of some, whereas the more general maxim "Lex orandi, lex credendi" suggests a general relationship between the two, Prosper of Aquitaine's formulation establishes the credence of certain Christian doctrines by placing their source in the Church's authentic liturgical rites, thus describing the liturgy itself as a deposit of extra-Biblical Christian revelation (part of a body of extra-Biblical beliefs known more collectively as Apostolic tradition), to which, in addition to Scripture, those who wished to know true doctrine could also refer.

As an ancient Christian principle it provided a measure for developing the ancient Christian creeds, the canon of scripture, and other doctrinal matters. It is based on the prayer texts of the Church, that is, the Church's liturgy. In the Early Church, there was liturgical tradition before there was a common creed, and before there was an officially sanctioned biblical canon. These liturgical traditions provided the theological (and doctrinal) framework for establishing the creeds and canon.

Catholicism
The principle is considered very important in Catholic theology. The Catechism of the Catholic Church states: "The Church's faith precedes the faith of the believer who is invited to adhere to it. When the Church celebrates the sacraments, she confesses the faith received from the apostles – whence the ancient saying: lex orandi, lex credendi, or legem credendi lex statuat supplicandi (the law of praying is to establish the law of believing) according to Prosper of Aquitaine. The law of prayer is the law of faith: the Church believes as she prays. Liturgy is a constitutive element of the holy and living Tradition."

However, in the encyclical Mediator Dei, Pope Pius XII elucidates but strongly limits this principle and address errors that can arise from a misunderstanding of it. He states: "46. On this subject We judge it Our duty to rectify an attitude with which you are doubtless familiar, Venerable Brethren. We refer to the error and fallacious reasoning of those who have claimed that the sacred liturgy is a kind of proving ground for the truths to be held of faith, meaning by this that the Church is obliged to declare such a doctrine sound when it is found to have produced fruits of piety and sanctity through the sacred rites of the liturgy, and to reject it otherwise. Hence the epigram, 'Lex orandi, lex credendi' - the law for prayer is the law for faith. 47. But this is not what the Church teaches and enjoins. The worship she offers to God, all good and great, is a continuous profession of Catholic faith and a continuous exercise of hope and charity, as Augustine puts it tersely. 'God is to be worshipped,' he says, 'by faith, hope and charity.' In the sacred liturgy we profess the Catholic faith explicitly and openly, not only by the celebration of the mysteries, and by offering the holy sacrifice and administering the sacraments, but also by saying or singing the credo or Symbol of the faith - it is indeed the sign and badge, as it were, of the Christian - along with other texts, and likewise by the reading of holy scripture, written under the inspiration of the Holy Ghost. The entire liturgy, therefore, has the Catholic faith for its content, inasmuch as it bears public witness to the faith of the Church. 48. For this reason, whenever there was question of defining a truth revealed by God, the Sovereign Pontiff and the Councils in their recourse to the 'theological sources,' as they are called, have not seldom drawn many an argument from this sacred science of the liturgy. For an example in point, Our predecessor of immortal memory, Pius IX, so argued when he proclaimed the Immaculate Conception of the Virgin Mary. Similarly during the discussion of a doubtful or controversial truth, the Church and the Holy Fathers have not failed to look to the age-old and age-honoured sacred rites for enlightenment. Hence the well-known and venerable maxim, 'Legem credendi lex statuat supplicandi' - let the rule for prayer determine the rule of belief. The sacred liturgy, consequently, does not decide or determine independently and of itself what is of Catholic faith. More properly, since the liturgy is also a profession of eternal truths, and subject, as such, to the supreme teaching authority of the Church, it can supply proofs and testimony, quite clearly, of no little value, towards the determination of a particular point of Christian doctrine. But if one desires to differentiate and describe the relationship between faith and the sacred liturgy in absolute and general terms, it is perfectly correct to say, 'Lex credendi legem statuat supplicandi' - let the rule of belief determine the rule of prayer. The same holds true for the other theological virtues also, 'In. . . fide, spe, caritate continuato desiderio semper oramus' - we pray always, with constant yearning in faith, hope and charity."

At a symposium held in connection with the publication of a set of reproductions of the first editions of the Tridentine liturgical texts, including the Roman Missal and the Roman Breviary, Archbishop Piero Marini, former Master of Pontifical Liturgical Celebrations, presented a paper entitled "Returning to the Sources", in which he said: "It is above all in the Liturgy that renewal cannot do without a sincere and profound return to the sources: sources of that which is celebrated and sources of that which is believed (lex orandi, lex credendi). Digging deep into the sources, the theologian and the liturgist aim simply to penetrate the profundity of the mystery of the faith as it has shown itself in the concrete life of the Church all through her history."

Pope Bendedict XVI' Summorum pontificum (2007) quotes the Roman Missal that "the Church’s rule of prayer (lex orandi) corresponds to her rule of faith (lex credendi)" (emph. added.) rather than e.g. determining or causing.

Lutheranism
The principle of lex orandi, lex credendi is found in Lutheranism. Professor of theology J. Matthew Pinson writes that "Liturgical theology shapes the sermon, which in turn gives life to the Liturgy, preventing it from degenerating into dead ritualism, mysticism, or superstition."

Anglicanism
Lex orandi, lex credendi is a fundamental character of Anglicanism. Its importance is due primarily to the fact that the Scriptures are the primary source of authority for Anglican theology.

The Archbishop of Canterbury, Thomas Cranmer, principal author of the prototypical 1549 Book of Common Prayer and the more reformed 1552 prayer book, could be said to be the first Anglican theologian. His theology is expressed in the selection, arrangement, and composition of prayers and exhortations, the selection and arrangement of daily scripture readings (the lectionary), and in the stipulation of the rubrics for permissible liturgical action and any variations in the prayers and exhortations – though, of course, his selections and arrangements were based on pre-existing continental Reformed theology. Gregory Dix, the Anglo-Catholic theologian has well said that Thomas Cranmer was a liturgical genius who helped to make the doctrine of justification by faith alone part of the common faith of England through the later 1662 Book of Common Prayer, which was faithful to the 1552 Book of Common Prayer. Elizabeth I, being Protestant, wanted to maintain the Protestant faith in England, though she did not allow the Puritans to regain control.

Given its locus in the worship of the Church, Anglican theology tends to be Augustinian and Reformed and embodies a strongly evangelical liturgy. The genius of Cranmer was in employing the principle of lex orandi, lex credendi to teach the English congregations the Reformed doctrines of grace and the sine qua non of the Gospel, justification by faith alone.

Orthodoxy
Eastern Orthodoxy's Patriarch Bartholomew I of Constantinople quoted this phrase in Latin on the occasion of the visit of Pope Benedict XVI, drawing from the phrase the lesson that, "in liturgy, we are reminded of the need to reach unity in faith as well as in prayer." Rather than regarding Tradition as something beneath Scripture or parallel to Scripture, Orthodox Christians consider Scripture the culmination and supreme expression of the church's divinely communicated Tradition. Councils and creeds recognized as authoritative are interpreted only as defining and more fully explicating the orthodox faith handed to the apostles, without adding to it.